Nitrogen　oxide　emissions　have　attracted　much　attention　due　to　their　impact　on　the　atmospheric　environment　and　human　health.　Combined　with　NO　removal　in　the　cement　production　process,　coal　gasification　slag　was　used　to　prepare　denitrification　materials　to　decompose　NO　in　cement　kilns　without　the　addition　of　reducing　agents.　Denitrification　materials　were　synthesized　by　a　chemical　precipitation　method　at　different　pH.　The　denitrification　mechanism　was　proposed　in　this　study.　The　results　indicated　that　the　denitrification　material　prepared　at　a　pH　of　7　exhibited　the　best　denitrification　performance.　The　NO　decomposition　rate　first　increased　and　then　decreased　below　400°C,　and　then　increased　as　the　temperature　increased,　reaching　over　97%　above　700°C.　In　the　low-temperature　range,　Fe(II)　was　assumed　to　be　active　species,　and　the　absorbed　NO　on　the　Fe(II)　site　obtained　an　electron,　which　promoted　the　decomposition　of　NO.　In　the　high-temperature　range,　besides　the　active　element　Fe,　the　residual　carbon　in　the　coal　gasification　slag　was　prone　to　oxidation-reduction　reactions,　reducing　nitric　oxide　to　nitrogen.　A　new　waste-to-value　concept　is　introduced　in　this　study,　which　promotes　green　technology　for　sustainable　development.　©　2023　American　Society　of　Civil　Engineers.